Various instruments and devices are used during orthopaedic arthroplasty procedures, such as, e.g., a knee arthroplasty procedure, to assist and guide the positioning of various instruments and devices used during the procedure.
For example, FIG. 1 shows a side view of a prior art external tibial alignment guide 10 attached to the lower leg of a patient which can be used during a knee arthroplasty procedure. The alignment guide 10 is used to position a tibial cutting block 12 against the tibial tubercle to perform a proximal tibial cut. The alignment guide includes an ankle clamp 14 by which the guide 10 is fixed distally to the patient's lower leg 16. The ankle clamp includes a block and a pair of clamps which engage around the ankle. The cutting block is attached to a telescopically extendable support member 18. The support 18 provides an external alignment guide by which the attached cutting block can be positioned and aligned relative to the longitudinal, inferior-superior axis of the tibia. That is, the support member can be aligned with the axis of the tibia.
The tibial resection position can be set using a stylus in combination with the cutting block 12 and once the height is selected, the cutting block can be pinned in place and the tibial cut performed.
However, the ankle clamp 14 gives rise to a number of problems. The ankle clamp can give rise to free, as well as accidental, translation and rotation, which will cause the alignment guide to move. Also, the ankle clamp can be difficult to use in practice as it requires manual manipulation and operation to clamp it around the patient. Further, during positioning around the patient, a users gloves can become caught in the clamp, which can delay the operation or require the gloves to be damaged and hence need replacing, causing further delays.
Hence, there is a need for a simple to use mechanism which allows instruments to be accurately and reliably attached to a patient.